Last week, we were reminded that Jerusalem was destroyed for the first time in 597 BC. That’s 2600 years ago. The city was demolished by the Babylonians, who were the superpower of the time. The Temple, God’s house, was torn down. And Jerusalem’s best and brightest were carried away into exile in Babylon, in the place we now call Iraq.

When the Jewish people were carried away, they felt they could no longer worship God. The Temple was gone. That was their only place of worship. So in Psalm 137 they sang,

By the rivers of Babylon
we sat down and wept
as we remembered Zion.
On the willow trees there
we hung up our lyres,
for there those who had carried us captive
asked us to sing them a song,
our captors called on us to be joyful:
‘Sing us one of the songs of Zion.’
How could we sing the Lord’s song
in a foreign land?

How indeed? As if broken hearts and broken spirits were not enough, how could they sing God’s songs with no temple?

The Book of Jeremiah countered this by telling them to put down roots, to grow food and have children, to pray for the welfare of the city of their enemies.

And when the time came that they could go back to their ancestral home, the Book of Jeremiah has startling news for the returning exiles. God says:

The days are surely coming, says the Lord, when I will make a new covenant with the house of Israel and the house of Judah…this is the covenant that I will make with the house of Israel…says the Lord: I will put my law within them, and I will write it on their hearts; and I will be their God, and they shall be my people.

The law had been written on stone tablets, and kept in the Temple. But this gave the people of Israel a new start. It slowly dawned on them that if they could carry God’s law in their hearts, they could worship God in places other than the Temple.

This new covenant God made with Israel is why Israel exists today. When Jerusalem was destroyed for the second time—this time by the Roman superpower in AD 70—and the Second Temple was made a heap of rubble, the Jewish people were used to worshipping in synagogues. Though they were scattered abroad by the Romans, the Jewish people could survive through century after hard century without the Temple.

That promise of God’s law being in our hearts belongs to us too. It’s part of the covenant God has made with us in Jesus Christ.

What is a covenant? A covenant is an agreement that involves promises and commitments and that binds two parties together. We enacted a covenant today when we baptised S, as we brought her into the covenant of baptism.

A covenant involves promises. What promises did we make today?

S’s parents and godmothers made promises on her behalf. They said they would ‘encourage S’s growth within the Christian community, guiding her through participation in the worship, nurture and fellowship of the Church to a mature Christian faith’.

That’s a big promise to make. But they weren’t content with just that, they also promised to ‘teach her the way of Christ until the Spirit draws her to make her own response in faith and love’.

Now, that’s what Sir Humphrey Appleby may call a ‘courageous’ thing to promise!

But we all made promises today. The rest of us said that we’d support them as we ‘continue a life of worship and teaching, witness and service so that this child and all the children among us may grow to maturity in Christ’.

Very courageous indeed!

Are we going to keep those promises, or are they just words? Are we going to keep the covenant of baptism?

Those aren’t the only promises made today. Our promises are useless on their own. What makes this something more than just ‘wetting the baby’s head’? The promises God makes, that’s what. God’s promises make baptism count. Without them, we may as well have stayed home.

We heard today that

Baptism is Christ’s gift.
It is the sign by which the Spirit of God
joins people to Jesus Christ
and incorporates them into his body,
the Church.

These are some of God’s promises to us. Baptism is a free gift to us—but more than that baptism is a covenant, a covenant that has been given to us by the risen Christ. God’s covenant promise to us is that baptism joins us to Jesus Christ—and we renew this covenant every time we receive the Sacrament of the Lord’s Supper. Remember what a covenant is? A covenant is an agreement that involves promises and commitments and that binds two parties together. S is now joined to Christ, she is part of his Body, the Church.

This is how a covenant is different from a contract. The two parties of a contract remain separate, you know ‘the party of the first part’ and ‘the party of the second part’. In the covenant of baptism, there is only one party, the Body of Jesus Christ which includes all the baptised joined to him.

That’s how the law of God is written in our hearts—through the Spirit of Jesus let loose in the world, the Spirit who takes our hearts and forms us into children of God.

In joining us to Jesus Christ as closely as one body part is joined to another, the aim of the covenant of baptism is for us to grow in Christ’s likeness. The aim is for his teachings to take root in our hearts. The aim is the same as Jeremiah’s new covenant:

I will put my law within them, and I will write it on their hearts; and I will be their God, and they shall be my people. No longer shall they teach one another, or say to each other, ‘Know the Lord’, for they shall all know me, from the least of them to the greatest, says the Lord; for I will forgive their iniquity, and remember their sin no more.

This is why we baptise, and why we have baptised S today. It is so God’s law will be written on her heart, the law of love that Jesus taught us. It is also to remind us that God’s law must be written on our hearts too, it’s to remind us to open and reopen our hearts to the Spirit of Christ.

And it’s to remind us of something even more surprising still: God forgets our sins! Whatever you may have done, God’s door is open to you. God forgets our sins. We rest on God’s promises; that’s how we can make our promises, and that’s why we are here as the Church in this place.